The main accomplishment during the past year has been the completion and publication of a research monograph on the theory of free energy transduction in biology. This gives a unified account of the various well-known examples of free energy transduction such as active transport, muscle contraction, oxidative phosphorylation, etc. The relations between steady-state kinetics and thermodynamics are emphasized. Work on explicit models of muscle contraction continues. The general approach we are using is set out in a paper with Evan Eisenberg. We hope to conclude the modelling work during the next year. Extensive mathematical analysis has been carried out on the steady-state kinetics of the respiratory chain enzymes. The latter part of this work, to be published in the near future, was in collaboration with Britton Chance. The same analysis is also applicable to single-file diffusion through membrane channels. BIBLIOGRAPHIC REFERENCES: Hill, T. L.: Free Energy Transduction in Biology. New York, Academic Press, 1977 (in press). Hill, T.L.: Steady-state kinetics of a linear array of interacting enzymes. In Landman, U. (Ed.): Statistical Mechanics and Statistical Methods in Theory and Application. New York, Plenum Press, 1977 (in press).